Under-memory array process edge mats with sense amplifiers

Abstract

An edge memory array mat with access lines that are split, and a bank of sense amplifiers formed under the edge memory array may in a region that separates the access line segment halves. The sense amplifiers of the bank of sense amplifiers are coupled to opposing ends of a first subset of the half access lines pairs. The edge memory array mat further includes access line connectors configured to connect a second subset of the half access line pairs across the region occupied by the bank of sense amplifiers to form combined or extended access lines that extend to a bank of sense amplifiers coupled between the edge memory array mat and an inner memory array mat.

What is claimed is: 
     
       1. An apparatus comprising:
 a first memory array mat comprising an access line segment formed in a first direction and coupled to a first count of rows of memory cells; 
 a second memory array mat formed adjacent an edge of the first memory array mat, the second memory array mat comprising:
 a first pair of access line segments formed in the first direction, wherein the first pair of access line segments are separated from each other by a respective space, wherein each of the first pair of access line segments is coupled to a second count of rows of memory cells; 
 a second pair of access line segments formed in the first direction and adjacent the first pair of access line segments, wherein the second pair of access segments are connected across the respective space via an access line connector to form a combined access line segment, wherein each of the second pair of access line segments is coupled to the second count of rows of memory cells; and 
 
 a first sense amplifier formed under an area between the first memory array mat and the second memory array mat, wherein the first sense amplifier is coupled to the access line segment of the first memory array mat and to the combined access line segment; and 
 a second sense amplifier formed under the respective space and is coupled to each of the first pair of access line segments. 
 
     
     
       2. The apparatus of  claim 1 , wherein the first and second edge memory array mats are formed using a stacked architecture. 
     
     
       3. The apparatus of  claim 1 , wherein the first and second edge memory array mats each include respective memory cells formed using a one transistor, one capacitor architecture. 
     
     
       4. The apparatus of  claim 1 , wherein the first and second edge memory array mats each include respective memory cells formed using a two transistor, two capacitor architecture. 
     
     
       5. The apparatus of  claim 1 , wherein the access line connector is formed using a common metal layer with the first and second pairs of access line segments. 
     
     
       6. The apparatus of  claim 1 , wherein the first count of rows of memory cells is greater than the second count of rows of memory cells. 
     
     
       7. The apparatus of  claim 1 , wherein the first sense amplifier is schematically similar to the second sense amplifier. 
     
     
       8. The apparatus of  claim 1 , wherein the first sense amplifier is schematically different than the second sense amplifier. 
     
     
       9. The apparatus of  claim 1 , wherein the first sense amplifier includes threshold voltage compensation circuitry. 
     
     
       10. The apparatus of  claim 1 , wherein the first and second sense amplifiers are formed using a complementary, metal-oxide semiconductor (CMOS) under array process. 
     
     
       11. An apparatus comprising:
 an edge memory array mat comprising:
 a first section comprising a first plurality of interleaving access line segments formed in a first direction, wherein each of the first plurality of interleaving access line segments is coupled to a count of rows of memory cells; 
 a second separated from an adjacent edge of the first section in the first direction by a space and comprising a second plurality of interleaving access line segments extending in the first direction, wherein each of the second plurality of interleaving access line segments is coupled to the count of rows of memory cells; and 
 a sense amplifier bank comprising a plurality of sense amplifiers formed over or under the edge memory array mat in the space between the adjacent edge of the first and second sections, wherein the plurality of sense amplifiers are coupled to a first subset of the first plurality of interleaving access line segments and a first subset of the second plurality of interleaving access line segments; and 
 a plurality of access line connectors configured to extend across the space to couple a second subset of the first plurality of interleaving access line segments to a second subset of the second plurality of interleaving access line segments to form a plurality of extended line segments. 
 
 
     
     
       12. The apparatus of  claim 11 , wherein the plurality of access line connectors are formed at a same metal layer as the first plurality of interleaving access line segments. 
     
     
       13. The apparatus of  claim 12 , wherein the sense amplifier bank extends in a direction perpendicular to the first plurality of interleaving access line segments. 
     
     
       14. The apparatus of  claim 11 , further comprising a second sense amplifier bank comprising a second plurality of sense amplifiers formed over or under the edge memory array mat adjacent the adjacent edge of the first section, wherein the second plurality of sense amplifiers are coupled to the plurality of extended line segments. 
     
     
       15. The apparatus of  claim 14 , wherein the plurality of sense amplifiers are schematically different than the second plurality of sense amplifiers. 
     
     
       16. The apparatus of  claim 15 , wherein the second plurality of sense amplifiers each include threshold voltage compensation circuitry. 
     
     
       17. A method comprising:
 forming an edge memory array mat of a memory array by:
 forming a plurality of access line segment pairs with each of the plurality of access line segment pairs separated at a common region; 
 forming a bank of sense amplifiers under the edge memory array mat extending along the common region perpendicular to the plurality of access line segment pairs with respective sense amplifiers coupled to odd pairs of the plurality of access line segment pairs; 
 forming a plurality of access line connectors configured to extend across the common region at a same level as the plurality of access line segment pairs, wherein each of the plurality of access line pairs is configured to electrically couple a respective even pair of the plurality of access line segment pairs together across the common region to form a respective combined access line. 
 
 
     
     
       18. The method of  claim 17 , further comprising:
 forming the plurality of access line segment pairs and the plurality of access line connectors using a first metal layer; and 
 forming the bank of sense amplifiers using a second metal layer. 
 
     
     
       19. The method of  claim 17 , further comprising forming the bank of sense amplifiers using a complementary, metal-oxide semiconductor (CMOS) under array process. 
     
     
       20. The method of  claim 17 , further comprising forming a second bank of sense amplifiers under the edge memory array mat along an edge opposite the common area with a second sense amplifier configured to couple to the combined access line segment and to an access line segment of an inner memory array mat.